Louis D

6 hours ago, bomberbaz said:

I am also considering this Svbony Wide Angle Eyepiece 1.25" Telescope Eyepiece 20mm FMC 68 Degree Astronomy Eyepiece for Telescope (20mm): Amazon.co.uk: Electronics & Photo does anyone own one, feedback would be great.

See my thoughts in the thread below:

Long story short, you wouldn't like it in your 12" scope.

Well, 5 years ago on August 21st, I was in Nebraska capturing this image:

But I have absolutely no idea what I was doing on August 11, 1999. 😁

Rather than live with that focuser kludge, I'd probably just buy a GSO 6" f/5 Newtonian Reflector Telescope (in stock) or GSO 6" f/5 Newtonian Reflector Telescope with LB Focuser Upgrade (once they're back in stock).  Since I already have a decent alt-az setup, along with plenty of storage space, this would make more sense for my situation, and possibly others as well.

This 6 year old thread (to the day) is the only one I know of anyone trying to add an R&P focuser to a SW Heritage scope:

4 hours ago, ED Splitter said:

I should have clarified. I am using a refractor. Depending on head/eye position the spike protrudes from the centre of the star and can move around the centre of the star much like a second hand around a watch face. So if I move my my eye off axis of a bright star the spike moves around the star if that makes sense. This only happens on bright stars. Perhaps I need to make some more observations and start a new thread. 

So, the spike spins around the star on the side opposite to wherever your moved your eye?  It sounds a bit like a reflection somewhere.  I've had bright planets have ghost images in some eyepieces that I can chase around the view in this same manner.  It's just weird that it extends as a spike rather than as a dimmer point of light.  Look down your eyepiece, diagonal, and focuser tube in daylight to look for shiny surfaces that may need flocking or at least blackening.

45 minutes ago, ED Splitter said:

I have the same eyepiece as the OP. Is this lack of field sharpness the reason why very bright stars develop a single a spike unless looked at perfectly on axis? 

 To my knowledge, the only cause of a single spike in a Dob/Newt would be if the secondary is held by a stalk rather than a spider.

If you were using a correct image diagonal in a refractor or cat, the Amici prism can also introduce a single spike on bright stars.

You're not referring to a lobe pointing away from the center of the FOV are you?  That could be coma, astigmatism, or lateral chromatic aberration.

6 hours ago, LaurenceT said:

Thanks for that Steve, I'll have a look at them. It seems that the real issue here is will I get enough improvement over the stock Skywatcher 28mm 2" EP by buying a sub £100 EP to justify the expenditure.

Probably any 4 element or more eyepiece would be an improvement over the SW 28mm three element eyepiece.  It's probably a Kellner or Konig variant, so not very good at f/6 or at 56° (28° half angle) AFOV.  Notice how spread out the dot plots get at just 10° off axis for simple designs at f/5:

However, notice that the Erfle type, even with 5 elements, is far from perfect.

In my experience, at f/6, most of the superwide eyepieces under $100 are probably sharp to about 50% to the edge and then start to degrade slowly until at around 75% out where sharpness rapidly declines to the edge.  If you only look on axis, they'll probably perform satisfactorily.  If you tend to let objects drift from edge to edge and watch them the entire way, you won't be pleased.

Another option might be to use a 2" focal reducer ahead of the binoviewer.  This would compress more field into the same image circle.  Some downsides would be an increased need for in-focus and outer field distortions.

You could contact Siebert Optics to see if they're still selling their 2" binoviewers.

UPS, FedEx, DHL, and Amazon always deliver to the front door, so less room for error as compared to cluster mailboxes.  This does risk porch pirates getting to your package before you do.

This does have the advantage over locked mailboxes in that once I see a package is delivered; but it isn't at my door, I can quickly go around the neighborhood checking porches for my package.  Again, only USPS has done this when they've run out of parcel lockers (the big ones in the cluster picture).  If you're wondering how parcel lockers work, they put the key in your regular mailbox (hopefully).  You then take the numbered key to the appropriate parcel locker, insert the key, unlock it, and retrieve your parcel.  The key is now locked into the keyway and the door slams shut, but not locked, on a spring.

We have 250 cluster mailboxes at the back of our subdivision, and it is all too easy for our postal workers to chuck mail into the wrong slot since they aren't well marked.

Unfortunately, I have indifferent neighbors who can't be bothered with being neighborly.  I think they consider misdelivered mail to be covered by this general rule in the US:

Under state and federal law, recipients of unordered merchandise may keep the goods and are under no obligation to pay for or return them.

9 hours ago, LaurenceT said:

As ever there are financial constraints so I'd be looking to buy used with a budget of around £70, any comments gratefully received.

There's not much in that price range, new or used, that will vastly improve the view in the outer reaches of the FOV at f/6.

If you doubled your budget, I'd recommend the 40mm Lacerta ED as a decent step up that gets you pretty close to 40mm Pentax XW level correction.  At 30mm, the APM UFF and it's other brandings is exceptional while not being TV priced.

You'll probably want to invest in a coma corrector at some point to clean up the edges and flatten the field a bit once you get eyepiece astigmatism under control (but not before).  The GSO CC is probably the best bang for the buck out there.  It's sold under many different brand names worldwide.

22 minutes ago, Don Pensack said:

USPS has not lost one package, though occasionally it takes an extra week or two to arrive, and I have had one misdelivery (which the homeowner delivered himself).

Lucky you to have a good neighbor.  Mine just silently keeps my misdelivered mail and packages.

Why wouldn't it be the default?  Does it draw too much power?  Only SW knows for sure.

I've never had UPS or FedEx lose a package in 30+ years of shipping items.  On the other hand, I've had the US Postal Service lose or misdeliver multiple items.  I once had over $1000 worth of jewelry delivered to my neighbor's mailbox.  They never deliver any of my stuff to me despite me dropping off theirs all the time.  Different attitudes, I guess.

I had to make the postal employee search their mailbox (they're locked) the next day to retrieve it without so much as an apology from them.  Luckily, my neighbor doesn't check snail-mail very often.  Once the USPS says an item is delivered, that's it.  There's no possibility of insurance claims or anything else.  They are infallible.

To really justify the asking price, the seller needs proper provenance papers showing it was actually used to film the original NASA missions of the '60s and '70s and the Challenger explosion as alluded to in the description.  At that point, it has serious collector value as a witness to history.  Otherwise, it may just be a surplussed spare that was never used.

What about designing a large format focal reducer for it to bring the focal ratio and focal length down along with shrinking the image circle to a more manageable size?

54 minutes ago, Zermelo said:

In Sky Safari, the "position indicator" (cross, finder circle or whatever option you have specified in the settings) will move on the chart to show the current pointing direction, which may or may not be on the chart displayed at the time. The chart can be dragged around to display where the indicator is, or positioned by choosing a new object and centering. So yes, you can just tap the object on the chart that matches what you see in the eyepiece, and display the associated information.

Sysncan also has an "identify" function, which looks for objects in its database that are near to (what it thinks is) the current pointing direction, but I think the Synscan database is much smaller.

 

I've never used Sky Safari.  I was thinking in terms of SkEye that keeps the pointing direction centered while slewing the map as needed to achieve this.  What's the advantage of not slewing the map to the current pointing direction in real time, map rendering time?  Is there an option in Sky Safari to turn this on, so you don't have to go hunting for the current position indicator every time you move the scope?

1 hour ago, badhex said:

Quick update on the ER experiments, I managed to test both EPs under the stars, and the spacing is perfect on both the Morpheus 4.5mm and the Superzoom. Makes a huge difference to comfort when using the EPs! 

Maybe we need to petition Baader to include several thin M43 sized O-rings for fine tuning the eye cup height as you did on the 4.5mm Morpheus.  They already include the useless clip for the eyepiece holster that's supposed to be used for tactile nighttime identification of eyepieces, so why not include something actually useful that costs pennies/pence in volume?

During Freedom Find mode, does the star chart in the app move in sync with the manually slewed scope, so if you see an object through the eyepiece that you want to identify, all you have to do is look at the app to see what's in or near the center of the current field of view?

21 minutes ago, badhex said:

I think I heard @Louis D use it first and was quite taken with it 😂

If I did use it first on here, it was only reusing a term from 50+ years ago.  Tupperware invented the airtight plastic storage container market years ago (at least in the US); and in commercials, they would refer to "burping" the lid to push out excess air (at about 35 seconds in):

5 hours ago, JeremyS said:

oh, one other thing. In a 1.25 inch eyepiece holder you need to rack the focuser way out compared to other EPs.

Do you mean way in, as in closer to the objective?  Racking the focuser outward mean extending it away from the objective in my experience.  The 2" lower barrel section on the SZ acts like a built in extension tube in 1.25" mode.  I get the same effect with Morpheus and similar eyepieces.

2 hours ago, badhex said:

Interesting combo! Was not aware of the PBI until you mentioned it - I must have missed your post.

Well, the TV PBI was discontinued over a decade ago, so I wouldn't expect you to have heard of it.  I think I bought the last one in stock at Adorama in 2010 for $60.

Since the intended Barlow for it, the TV Big Barlow, has basically the same focal length as the GSO ED 2" 2x Barlow, the latter works well with the PBI.  On the other hand, I tried it with my 1990s Japanese made Orion 2" 2x Barlow which has about a 50% longer focal length, and the combo is horrific.  I have no words for the very odd distortions going on with those two.  It hurts the brain trying to focus on objects when viewing through that combo.

Thus, serendipity for the GSO/PBI combo.  That, or GSO simply copied the TV BB optical design.

5 minutes ago, badhex said:

Cheers Louis. Very helpful that some of these EPs have various permutations and options to vary ER for those that need it - perhaps the M43 rings should be a standard for eyeguards. 

The Astro-Tech AF70 (Omegon Redline SW, etc.) have M43 eye cups as well, just extremely stiff.  They basically can't be folded down at all, so I have to unscrew and remove them altogether.  Here's an image of mine showing the eye cup attached to the 17mm version:

M43 is a fairly common size for eyepieces, video cameras, and digital camera adapter tube filter threads.  I believe the 24mm APM UFF has that thread size as well.  However, the 30mm APM UFF has an M45 thread, so not universal even with the UFF line.

7 hours ago, badhex said:

Upgraded my 2" GSO barlow to a Powermate! 

Let us know how it interacts with your 2" eyepiece collection.  I have a poor-man's 2x 2" Powermate, a 2" 2x GSO ED Barlow + TV PBI.  It works well with most eyepieces, but not all.  Here's my findings back on July 9th:

Next, I tried them all in a GSO ED 2x 2" Barlow with a Tele Vue Panoptic Barlow Interface without the GSO CC since I don't have enough in-focus for both at the same time.  Surprisingly, the 40mm Lacerta didn't improve very much at the edge.  The 35mm ED improved a bit more, but was not perfect.  The 40mm Pentax didn't play well at all with it.  The outer field wasn't sharp anymore.  The 40mm Meade SWA worked exceptionally well with the Barlow, showing a sharp edge and flat field.  The 35mm Scopos and 26mm MWA both worked well Barlowed, but there was a bit of exit pupil instability with the former and no change in SAEP with the latter.  The 40mm Lacerta was a bit tight in the TV PBI, but not as bad as in the GSO CC.